The present invention relates to a brake mechanism for a device for hauling up/down by rope, in particular one for the safe hauling up and down by rope of persons and loads. The device has a pulley which preferably has a back stop that prevents the pulley from turning during the roping down.
In accordance with the European published patent EP-A-0 480 117 by the applicant, such devices for hauling up/down by rope are preferably used for hauling persons or loads up and down on a rope. The preferred area of application is for rescue services or in general as mobile equipment. The devices for hauling up/down by rope essentially function to reduce the retaining force during the roping down in connection with a safety to prevent an uncontrolled dropping of the person or load attached to the rope.
These known devices for hauling up/down by rope have a large-volume pulley equipped with a back stop. In most cases, a rope is placed with 2.5 windings around this pulley. The device is operated such that when pulling up, the pulley is running freely and represents only a low resistance. During the roping down, on the other hand, the pulley is blocked by the back stop and the rope slides over the surface of the pulley. The resulting friction takes over a large portion of the load attached to the rope.
As a safeguard during the roping down, the International Patent Application WO-A-9 717 107 suggests providing a self-activating rope stop on the pull side of the device for hauling up/down by rope. The advantage of this arrangement is that the rope stop only needs to take over a portion of the load since the device for roping up/down accepts the largest portion of the pull.
However, the disadvantage of this solution is that upon reaching the critical roping down speed, the roping down operation is stopped completely. In particular if a roping down speed near the permissible limit, e.g. 2 m/s, is required, a brief exceeding of this speed limit can trigger the stopping of the rope.